Floating roof



July 15, 1958 R. c. ULM 2,843,289

FLOATING ROOF Filed Aug. 9, 1956 2 Sheets-Sheet 1 R. C. ULM

FLOATING ROOF July 15,1958

2 Sheets-Sheet 2 Filed Aug. 9, 1956 INVENTOR.

jggg uz 2%)? FLQATING ROOF Application August 9, 1956, Serial No. 603,004

2 Claims. (Cl. 220-26) The invention relates to floating roofs used in large liquid storage tanks, and particularly to a novel centrally weighted arrangement for a single deck-type floating roof.

Those familiar with the art of liquid storage tanks will understand certain characteristics heretofore found in the use and operation of centrally weighted single deck floating roofs. As is well known in the art, roofs of this type are provided with a centrally located sump which has portions thereof below the level of the deck and may further be provided with peripherally arranged pontoons to add to the buoyant effect at the outer portions of the roof. In the past, the combination of the central weight and the pontoon effect at the periphery of the roof was designed to pitch all portions of the roof downwardly toward the center and particularly the sump whereby, roof collected foreign matter such as rain, would be urged to flow to the sump from whence it could be evacuated in a conventional manner thereby avoiding possible roof sinking and other hazards. An important consideration in the design of this type of roof is total roof weight in that the heavier roofs result in an important reduction in available tank capacity, this reduction varying with the quality of liquid stored. An additional important consideration is that the heavier roofs are considerably more expensive to manufacture and therefore result in a higher initial cost. Prior art centrally weighted type roofs have characteristically been extremely heavy whereby disadvantages of relatively high initial cost and reduced tank capacity have as a result been inherent with this type of roof.

Accordingly, it is a primary purpose of the invention to provide a-comparatively light Weight, centrally weighted single deck-type floating roof having improved characteristics over those heretofore found in the art.

It is a further and more specific object of the invention to provide a light weight floating roof of the type described having a novel center structure which provides for and accommodates varied weighting of the central portion of the roof, but nevertheless functionally satisfies the drain requirements incident to satisfactory roof operation.

A further advantage of the disclosed invention is that .it allows the deck of the roof to be built flat and eliminates complicated and heavy roof under structure.

These and other objects of the invention will become apparent in the course of the following description and from an examination of the associated drawings, wherein:

Figure 1 is a fragmentary plane view of a typical floating roof embodying the invention,

Figure 2 is a fragmentary sectional view taken substantially along line 2-2 of Figure 1,

Figure 3 is a detailed view taken along line 33 of Figure 2 with the roof deck removed,

Figure 4 is a sectional view taken along line 4-4 of Figure 3,

Figure 5 is a sectional view similar to Figure 3, but illustrating a slight modified embodiment of the invention, and

hired tates Patent 6 Figure 6 is an elevational view taken along lines 66 of Figure 5.

Describing the invention in detail and directing attention to the drawings, it will be seen that the roof comprises a generally planer deck 2 having a rim 4 peripherally secured thereto adjacent the outer edge of the deck. Radially inwardly from the rim 4 another upstanding annular member 6' is provided, said member being in determined spaced relation to the rim 4. It will 'be noted that the deck 2, as seen in section View, angles downwardly and outwardly, as at 8, from the approximate point of attachment of the member 6 to the deck 2. Radially arranged elements 10 may be provided to interconnect the member 6 and rim 4, and further an annularly arranged re-inforcing ring 11 may be secured to the deck intermediate the member 6 and rim 4, all of which serves to add strength and rigidity to this outer pontoon-like section of the roof. Additionally, bulkheads 12 12 may be arranged to interconnect the portion 8 of the deck 2 and the member 6 and the rim 4 at determined points around the periphery of the rim. The section may be closed by an addition of generally horizontally arranged covering plates 14 which extend between the upper extremity of the member 6 and connect to the rim 4 at a point adjacent the top thereof. A plurality of vapor vent pipes 16 establish communication between the area below the roof and the area outboardly of the roof at the rim 4, as best seen in Figure 2. If desired, pontoons may be located under the deck 2.

Considering the central portion of the roof, it will be seen that a sump 17 is provided thereon, said sump being arranged to collect water and other foreign material, and has disposed therein a conventional hose drain 18, arranged to accommodate the drainage and removal of foreign matter from the sump.

A plurality of longitudinal box-like channels 20 are radially arranged from the central sump 17 to extend outwardly therefrom. In the preferred embodiment these channels are secured to the underside of the deck 2 and are arranged to receive and confine appropriate weights 22. An annular re-inforcing angular ring 24 may then be secured to the underside of the deck 2 immediately adjacent the outboard ends of the channel 20. Further, the rings 24 are secured to the channels to offer certain support therefore.

It should be particularly noted that the confining channels 20 are of such a nature that they can be variably loaded with appropriate weighting material such as, for example, scrap steel or metal ingots. Thus, when a roof is constructed at the tank site, varying amounts of weighting material may be added to the channels to satisfy the functional demands of that particular roof. Additionally, it is possible to easily vary the loading of the central portion even after the roof is in service, if desired. The channels 20, when combined with the stress distributing characteristics of the annular ring 24, offers such loading of the central section so that the operating roof is provided with a proper pitch to drain inwardly toward the sump. I have discovered that this particular channel and stress distributing arrangement provides a roof having all the desired functional characteristics as heretofore mentioned and additionally provides a roof of considerably lighter initial construction and further requires considerably less weight to properly weigh the central section to achieve the desired result. This, of course, offers both initial savings in construction cost and also increases the liquid capacity of the tank with which the roof is associated.

Considering Figures 5 and 6, it will be seen that I have illustrated a slight modification of the arrangement wherein the radial channels 30 are quadrantally arranged about the central sump 17. The annular stress distributing ring 24 is again provided and again secured to the outermost extremities of the channels 30. In this embodiment, I also provide a single strip 32 at the outer open end of each channel 3% to act as a retainer to maintain the variable weight, such as ingots or the like, within the confines of each channel 30.

It will be understood that the invention shown is by Way of illustration and not limitation and may be subject to various modifications without departing from the spirit thereof or the scope of the appended claims.

What is claimed is:

1. In a field storage tank arrangement comprising a cylindrical shell, a roof arranged to float on product stored in the shell, said roof comprising a single deck, a rim peripherally secured adjacent the outer edge of the deck, a plurality of pontoon-like sections peripherally located around the outer edge of the deck, a sump centrally located on the deck and comprising a wall secured to the underside of the deck and defining a sump chamber below said deck, drain means operatively connected to the sump, and means to accommodate selectably variable uniform loading of the central portion of the said roof immediately adjacent said sump so as to provide said deck with a selectably variable positive downward pitch toward said sump, said means comprising a plurality of box-like chambers extending radially outwardly from said sump below said deck, said box-like chambers being radially elongated and provided with equal angular spacing therebetween, said box-like chambers being arranged to selectably receive variable but equal quantities of weighting material, and a unitary annular stress-distributing member continuously connected to the underside of said deck and the outer extremity of said box-like chambers.

2. A field storage tank arrangement according to claim 1, wherein said wall defines the radially inner extremity of all of said box-like chambers.

References Cited in the file of this patent UNITED STATES PATENTS 2,464,786 Allen Mar. 22, 1949 2,497,047 Prager et al. Feb. 7, 1950 2,538,033 Orr Jan. 16, 1951 FOREIGN PATENTS 729,506 Great Britain May 4, 1955 

